Reliability evaluation of MMC system considering working conditions

Abstract

The reliability is a key issue of the high-voltage high-power modular multilevel converter (MMC) system due to the usage of fragile insulated gate bipolar transistor (IGBT) modules. In this study, it is proposed that the reliability of the MMC system can be modelled and calculated considering practical working conditions. Firstly, based on the MMC power level, the power loss and the junction temperature are analysed. Then considering the aging process of IGBT, the failure rate is calculated with temperature coefficient. Finally, the MMC system failure rate and its relationships with some key parameters are found.

Keywords

• ageing
• insulated gate bipolar transistors
• voltage-source convertors
• HVDC power convertors
• failure analysis
• reliability
• power loss
• MMC system failure rate
• reliability evaluation
• high-voltage high-power modular multilevel converter system
• fragile insulated gate bipolar transistor modules
• MMC power level
• working conditions
• junction temperature
• temperature coefficient
• IGBT aging process